Software defined radio (SDR) is a scheme in which multiple wireless communication standards are supported in a wireless transmit/receive unit (WTRU) and radio frequency (RF) signals are processed by software defined units. With SDR, a single hardware platform can support multiple wireless communication standards without replacing hardware components, and downloaded software can reconfigure the hardware. In this way, WTRUs can be rapidly configured to support newly developed wireless communication standards and protocols.
Currently, WTRUs are configured to process multiple services received through multiple channels. For example, a WTRU may support communications both in a digital cellular system (DCS) and a wideband code division multiple access (WCDMA) system. Each service is processed through a corresponding receiver path in the WTRU and separately input into a modem in the WTRU for processing. However, only one service is supported at a given time in each receiver path.
Current WTRU designs also include front-end configurations that involve a switch or a multiplexer and multiple filters that separate the signals into different receiver paths for the frequency band of each service. Each receiver path requires separate filters, a down-converter, a demodulator and local oscillators (LOs). Therefore, prior art WTRUs require extensive hardware resources to support multiple services and the configuration is not desirable in terms of battery life of the WTRU.